Hydraulic track drive with hydraulic track tensioners

Abstract

A light weight track drive mechanism that provides a large track drive surface area while maintaining a low weight to track contact surface area ratio so that the track drive could operate on soils with low support qualities. In addition, the track drive system is provided with high ground clearance so that fewer obstacles may prevent the track drive from moving around as needed.

What is claimed is:  
     
       1. A hydraulic track drive with hydraulic track tensioners comprising: 
       a drive chassis including a cab support structure and left and right sets of plurality of pairs of free-wheeling pneumatic tires rotatably mounted, respectively to, left and right wheel structures of the drive chassis;  
       left and right loops of drive track;  
       a housing assembly;  
       left and right hydraulic motors;  
       left and right drive sprockets;  
       left and right drive hydraulic pumps;  
       left and right drive control valving;  
       left and right track tensioner assemblies;  
       tension control valving;  
       a tensioner assembly hydraulic pump;  
       left and right chain guides; and  
       a pump drive motor for driving the tensioner assembly hydraulic pump and the left and right hydraulic motors;  
       the left and right loops of drive track each being moveably entrapped around respectively, a left or a right set of the plurality of pairs of free-wheeling pneumatic tires, a left or a right chain guide and a respective left or right drive sprocket;  
       each of the left and right loops of drive track having an inwardly facing track drive track chain along the entire length thereof;  
       each pair of free-wheeling pneumatic tires having an inner pneumatic tire and an outer pneumatic tire between which a drive track chain gap is provided;  
       each drive track chain gap of each pair of free-wheeling pneumatic tires being in alignment with each of the drive track chain gaps of its respective set such that a track drive track chain passageway is formed therebetween for passage of the track drive track chain of the respective loop of drive track;  
       each of the chain guides being supported by the drive chassis above its respective track drive track chain passageway;  
       each of the chain guides being open at the track drive facing surface thereof and sized to receive and slidably support sections of the inwardly facing track drive track chain of a respective left or right loop of track drive as the respective left or right loop of track drive is forced along a closed path by the respective left or right drive sprocket;  
       the respective left or right drive sprocket each being in alignment with its respective track drive track chain passageway and meshed with its respective track drive track chain of its respective loop of drive track such that rotation of the respective left or right sprocket causes a movement of the respective loop of drive track and the respective set of the plurality of pairs of free-wheeling pneumatic tires;  
       the housing assembly having the left and right hydraulic motors housed within respective left and right ends thereof, hydraulic lines in connection with the left and right hydraulic motors extending from the housing assembly and in connection with the left and right drive control valving and the left and right hydraulic pumps such that an operator can control the speed and direction of each of the left and right hydraulic motors;  
       the left and right sprockets being driven, respectively, by the left or right hydraulic motor;  
       the housing assembly being moveably coupled to the drive chassis by spaced left and right slide members each slidably supported within one of two spaced slide member receiving tubes by a pair of resilient bushings;  
       each slide member receiving tube being in a rigidly supported position with respect to the drive chassis;  
       the left and right track tensioner assemblies each including a respective left or right double acting hydraulic cylinder mechanically coupled between the drive chassis and an exterior of the housing assembly such that the housing assembly is moveable in all three planes with respect to each of the left or right double acting hydraulic cylinders;  
       the left or right double acting hydraulic cylinders each being in hydraulic connection with the tension control valving and the tensioner assembly hydraulic pump such that an operator can adjust the tension applied to a respective left or right loop of drive track by the respective left and right sprocket by operation of the tension control valving;  
       the tension control valving, the left and right drive control valving, the tensioner assembly hydraulic pump, the left and right hydraulic pumps, and the hydraulic pump drive motor being supported by the drive chassis.